Chapter 7 Firewall for FortiOS 5.0 : Security policies : Interface Policies : IPv6 IPS
  
IPv6 IPS
IPv6 IPS signature scan can be enabled by interface policy. The user can create an normal IPS sensor and assign it to the IPv6 interface policy.
config firewall interface-policy6
edit 1
set interface "port1"
set srcaddr6 "all"
set dstaddr6 "all"
set service6 "ANY"
set ips-sensor-status enable
set ips-sensor "all_default"
next
end